IAT: Add a few regression tests

tests/ui/associated-inherent-types/issue-109768.rs

@@ -0,0 +1,12 @@
+// incremental
+
+struct Wrapper<T>(T);
+
+struct Local<T, U>(T, U);
+
+impl<T> Local { //~ ERROR missing generics for struct `Local`
+    type AssocType3 = T; //~ ERROR inherent associated types are unstable
+
+    const WRAPPED_ASSOC_3: Wrapper<Self::AssocType3> = Wrapper();
+}
+//~^ ERROR `main` function not found

tests/ui/associated-inherent-types/issue-109768.stderr

@@ -0,0 +1,35 @@
+error[E0601]: `main` function not found in crate `issue_109768`
+  --> $DIR/issue-109768.rs:11:2
+   |
+LL | }
+   |  ^ consider adding a `main` function to `$DIR/issue-109768.rs`
+
+error[E0107]: missing generics for struct `Local`
+  --> $DIR/issue-109768.rs:7:9
+   |
+LL | impl<T> Local {
+   |         ^^^^^ expected 2 generic arguments
+   |
+note: struct defined here, with 2 generic parameters: `T`, `U`
+  --> $DIR/issue-109768.rs:5:8
+   |
+LL | struct Local<T, U>(T, U);
+   |        ^^^^^ -  -
+help: add missing generic arguments
+   |
+LL | impl<T> Local<T, U> {
+   |              ++++++
+
+error[E0658]: inherent associated types are unstable
+  --> $DIR/issue-109768.rs:8:5
+   |
+LL |     type AssocType3 = T;
+   |     ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #8995 <https://github.com/rust-lang/rust/issues/8995> for more information
+   = help: add `#![feature(inherent_associated_types)]` to the crate attributes to enable
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0107, E0601, E0658.
+For more information about an error, try `rustc --explain E0107`.

tests/ui/associated-inherent-types/issue-109789.rs

@@ -0,0 +1,22 @@
+#![feature(inherent_associated_types)]
+#![allow(incomplete_features)]
+
+struct Foo<T>(T);
+
+impl Foo<fn(&'static ())> {
+    type Assoc = u32;
+}
+
+trait Other {}
+impl Other for u32 {}
+
+// FIXME(inherent_associated_types): Avoid emitting two diagnostics (they only differ in span).
+// FIXME(inherent_associated_types): Enhancement: Spruce up the diagnostic by saying something like
+// "implementation is not general enough" as is done for traits via
+// `try_report_trait_placeholder_mismatch`.
+
+fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
+//~^ ERROR mismatched types
+//~| ERROR mismatched types
+
+fn main() {}

tests/ui/associated-inherent-types/issue-109789.stderr

@@ -0,0 +1,21 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-109789.rs:18:1
+   |
+LL | fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+   |
+   = note: expected struct `Foo<fn(&'static ())>`
+              found struct `Foo<for<'a> fn(&'a ())>`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-109789.rs:18:11
+   |
+LL | fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+   |
+   = note: expected struct `Foo<fn(&'static ())>`
+              found struct `Foo<for<'a> fn(&'a ())>`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/associated-inherent-types/issue-109790.rs

@@ -0,0 +1,17 @@
+// check-pass
+
+#![feature(inherent_associated_types)]
+#![allow(incomplete_features)]
+
+struct Foo<T>(T);
+
+impl<'a> Foo<fn(&'a ())> {
+    type Assoc = &'a ();
+}
+
+trait Other {}
+impl Other for u32 {}
+
+fn bar(_: for<'a> fn(Foo<fn(&'a ())>::Assoc)) {}
+
+fn main() {}